Big Problems - oh no!
 

I have very large vB forums and have noticed that all the search engines are indexing many of the same page with various urls, even though I bock all pages except for showthread.php in robots.txt.

For instance... google has indexed the following versions of the same showthread.php thread:

/showthread.php?p=48043&mode=linear
/showthread.php?mode=hybrid&t=2491
/showthread.php?t=2490&goto=nextoldest
/showthread.php?p=48043&page=2&pp=25
/showthread.php?t=2491&page=1&pp=25
/showthread.php?goto=lastpost&t=2491
/showthread.php?p=50108&mode=linear
/showthread.php?p=48043&mode=threaded
/showthread.php?p=50108&mode=threaded

NOTE: All these links point to the EXACT same thread!!!

I have looked around at other vB forums on the net and no one else has this problem. Is there anyway to stop this? Thanks for your help!

What's happening is Google is spidering your site and finding the links to the different versions of the linear or threaded or different types of links, it may be because of your members viewing habits where they link to a thread with different types of links and google catches it and spiders it.

Any idea how this can be fixed???... about 100,000+ (I am guessing.. since google will only show me couple thousand approx.) all have been indexed in the various ways listed above... making my forums sit in the "supplemental" index because of duplicate content.

Oldie but maybe goodie: https://vborg.vbsupport.ru/showpost.php?p=609808

I wouldn't think so Calorie, that's 3.0.x code :(

peterska2, it should still be okay as long as the following isn't a vB page, but this was true then also.
PS: you could stick the code in a plugin using the init_startup hook.