Email filtering methods and systems

• US 7,490,131 B2
• Filed: 06/26/2006
• Issued: 02/10/2009
• Est. Priority Date: 02/04/2000
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Maller, Steven T.
• Primary Examiner(s): Vaughn, Jr.; William C
• Assistant Examiner(s): Shingles; Kristie D
• Application Number:
  US11/426,379
• Publication Number:
  US 20070061404A1
• Time in Patent Office: 960 Days
• Field of Search: 709/206, 709/207, 709/240, 709/228
• US Class Current: 709/206
• CPC Class Codes: H04L 51/212 using filtering or selective blocking
• CPC Class Codes: H04L 51/42 Mailbox-related aspects, e.g. synchronisation of mailboxes

Abstract

Various embodiments of the invention address two critical problems that current email service providers face. First, there is the problem of maintaining high levels of customer service when email server systems are inundated with spam. Second, there is the problem of reducing the system-wide impact that spam has on the email delivery system. Current embodiments are directed to determining whether an email message is an unwanted bulk email message without necessarily considering the message that is conveyed by any portion of the email message. Through analyses of patterns of delivery of these email messages, profiles are built that allow an email server to ascertain whether there is a likelihood that any one particular email message constitutes an unwanted email message. If an email message is determined to likely constitute an unwanted email message, then memory-saving measures are implemented. In preferred embodiments, one copy of the email message is saved at a central, shared location that can be accessed by each of the intended recipients. This avoids having to replicate the email message across the system for each of the recipients.

Claims

1. A computer-implemented email filtering method comprising:

defining at least one heuristic that determines whether an incoming email message likely constitutes unsolicited email by considering an established delivery pattern that such unsolicited email typically exhibits when it is sent, wherein the at least one heuristic is independent of a message conveyed by any content of the email message, including content of the sender address field, subject field and message field, and wherein the pattern is associated with a percentage of specified recipient addresses of the email message that are invalid specified addresses;

applying the at least one heuristic to the email message; and

redirecting the email message if application of the at least one heuristic indicates that the email message likely constitutes unsolicited email, wherein redirecting comprises placing a copy of the email message at a location not dedicated to storage of just one user'"'"'s email.

2. The computer-implemented email filtering method of claim 1, wherein the location comprises a location from which the copy can be accessed by more than one intended recipient of the email message.

3. The computer-implemented email filtering method of claim 1, wherein the at least one heuristic has at least one parameter that can be adjusted to vary the pattern that is considered.

4. The computer-implemented email filtering method of claim 1, wherein the pattern is associated with a number of specified recipient addresses of the email message.

5. The computer-implemented email filtering method of claim 1, wherein the pattern is associated with a size of the email message.

6. The computer-implemented email filtering method of claim 1, wherein the pattern is associated with a number of invalid specified recipient addresses of the email message.

7. The computer-implemented email filtering method of claim 1, wherein the location can be shared by a plurality of intended recipients for reading the email message, and wherein the method further comprises after the redirecting, notifying intended recipients of the email message that an email message intended for them has been redirected to the location.

8. One or more computer-readable storage media comprising computer-executable instructions that, when executed, perform acts comprising:

defining one or more heuristics to determine whether an email message likely constitutes unsolicited email by considering one or more established delivery patterns that such unsolicited email typically exhibits when it is sent, wherein at least one of the heuristics is independent of the message conveyed by any content of the email message, including content of the email message'"'"'s sender address field, subject field and message field, and wherein at least one of the heuristics determines a percentage of specified recipient addresses of the email message that are invalid;

applying the one or more heuristics to the email message; and

redirecting the incoming email message if application of the one or more heuristics indicates that that the email message likely constitutes unsolicited email, wherein redirecting comprises placing a copy of the email message at a location not dedicated to storage of just one user'"'"'s email.

9. The one or more computer-readable storage media of claim 8, wherein the copy can be accessed by more than one intended recipient of the email message.

10. The one or more computer-readable storage media of claim 8, wherein at least one of the heuristics has a parameter that can be adjusted to vary one of the one or more patterns considered.

11. The one or more computer-readable storage media of claim 8, wherein at least one of the one or more patterns is associated with a number of specified recipient addresses of the email message.

12. The one or more computer-readable storage media of claim 8, wherein at least one of the one or more patterns is associated with a size of the email message.

13. The one or more computer-readable storage media of claim 8, wherein at least one of the one or more patterns is associated with a number of invalid specified recipient addresses of the email message.

14. A computer-implemented method comprising:

receiving an email message at an email server that maintains inboxes for individual recipients;

calculating a score for the email message at the server based on one or more parameters having parameter values associated with the likelihood of whether an email message constitutes an unwanted email message;

comparing the score with a threshold value that defines a likelihood of whether an email message constitutes an unwanted email message, wherein the parameters and the threshold value are adjustable, wherein the score is based at least in part on one or both of;

a number of invalid specified recipients of the email message, or

a percentage of specified recipient addresses of the email message that are invalid;

responsive to the email message exceeding the threshold value, placing a copy of the email message at a first location other than an individual storage location dedicated to an individual intended recipient of the email message; and

sending a notification to intended recipients of the email message that a copy of an email message that was intended for them has been placed at the first location.

15. The computer-implemented method of claim 14, wherein the threshold value is determined independent of the message conveyed by any of the text that is contained in any part of the email message.

16. The computer-implemented method of claim 14, wherein the score is based at least in part on one or both of:

the email message size;

or

a number of specified recipient addresses of the email message.

17. The computer-implemented method of claim 14, wherein the first location is a storage location managed by the email server.

18. The computer-implemented method of claim 14, further comprising responsive to a request from a recipient making a recipient copy of the email message and placing the recipient copy at a dedicated recipient storage location.

19. One or more computer-readable storage media having computer-readable instructions thereon which, when executed by a computer, implement the method of claim 14.