showing non readable items with 'new' sign next to it?

I have noticed recently in SMF forums for a user if the item is not read , it is showing 'new' next to the item . I can implement it using browser based cookies . But for SMF for same user if I login from different machines also it maintains the status . They must be putting some tag at server end . I am wondering how can they keep the status at server end for each item and for each user end server end ? Could som开发者_如何学运维ebody advise me on this ?

Thanks for your help

Regards

Kiran

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Kiran,

From what I've read, SMF has a number of tables in its database dedicated to storing "log" information about which users have browsed which boards/topics/threads. At each level, users have the ability to maintain their history, either by browsing to each board/topic/thread, or by using the UI to "mark as read" a specific section. This sets the log entry at every level to indicate "User X has read up until this timestamp." Then, upon further pageload, and new posts that occur after that timestamp will appear as new/unread.

I'm basing this off of this thread on how people are using these tables to "compress" people's reading histories.

http://www.simplemachines.org/community/index.php?topic=212330.msg1667071#msg1667071

Regards,

Kaiden