For example, if you go to this page:
http://forums.silentpcreview.com/viewforum.php?f=1
You get a list of the most recently posted-to topics in the "General Discussion Forum". Right now, the info provided for each post is the replies, author, views and date and author of last post. I think it may be useful to also see the date that the topic was started while in this view. This information is currently only available by clicking on a topic name and looking at the tiny print that says the date and time of the original post.

An example of where this might make a difference is with the recent activity in the "98W max power consumption" thread, which has been revived in the past couple of days, but was written back on what is apparently the oldest day the forums record, August 12, 2002.

I think the best place to include the date info for the topic is in the column currently used for "Author". Instead of displaying just the Author's name, it could display the Author's name and the date the topic was started, similar to the current entry for "Last Post". I would arrange it such that the Author's name is on top and the date of the topic is on bottom (opposite of how it is for "Last Post").

As always, this proposal is only useful if it isn't pointlessly hard to implement, and if it provides positive value to the forums. The only negative I can think of for this proposal is that it might clutter up the forum index view, but as long as certain design cues are followed (Author's name in blue, date smaller(?) and in black), I don't think this will be a problem.

I like the start date idea. IMO a lot of the recently resurrected posts have been by friendly neighborhood spammers looking for something else to tack a post to or by newbies who may not have lurked long enough to realize their question may be answered more recently in another thread.
So, I agree, as the forums grow, the total posts grow, and even those who are here every day can't always remember what's old and what's new. However, an old start date is not always an indication that someone is dusting off a deceased thread. Just that the discussion started a while ago.

Formatwise, I would differ with what I've quoted above and vote for the format to be the same as the Last Post column (date on top and Author below).
(I'm so not postmodern. I love symmetry. )

I saw a board (I think it was running Invision) that showed the topic start date as a tooltip when you hovered the mouse over the topic thread hyperlink. I'm not sure if this is possible in phpBB, but it worked great, since it made the information easily viewable without requiring the addition of another column.

Adding another column for (IMO, only semi-relevant information) would not only clutter the forum views, but also stretch the screen so that an 800x600 display could no longer display the forum indexes (indices?) without a bottom scrollbar appearing.

Edit: Personally, I have nothing against the revival of old threads, if the new posts are relevant to the thread. It just means there's one less thread to search for if I'm looking for information. Ideally, all threads discussing an identical topic would be combined into a single thread, so all the information would be in one place. That is, as long as we don't start getting 20+ page threads that show up on some forums. That's even worse than a bunch of small threads, because no one ever reads through all the pages (unless they have a spare afternoon).

Edit 2: I just tested the forum at 800x600 (in Mozilla Firebird 0.6), and currently a bottom scrollbar shows up, but the outside blue border of the forum table is just visible, so nothing is really hidden on the right side of the screen. Adding anything to the index view, though, would push information off the side of the monitor.

Limiting the posted date to just month, day, year would keep the column as narrow as it is currently with the avatar names. Would that be too little information to be helpful? Can't see where there is a need to add day of week or time, unless truncating that from the database info would be too much work for the admin.