Not Receiving Tweets Over IM When Not Signed In To IM

When I first started using Twitter over IM (with GTalk), each time I signed into IM I would get all of the tweets since the last time I was signed on. This is no longer the case. Now when I sign in to my IM account I only get tweets from the point in time when I signed in.

This problem MAY have arisen around the same time that I tried out Twitterific, but I can't be sure...