mThink

The Microsoft/Yahoo PPC alliance was always going to have teething troubles and give advertisers some headaches. We are gradually learning just where those are going to come from.

The most complicated issues are likely to spring from the differences in the way that Yahoo Search Marketing and Microsoft’s adCenter treat keywords. adCenter in general provides much finer control over management of keyword mis-spellings and plurals, significantly greater limits on negative keywords, as well as taking a different approach to geo-targeting.

Today Facebook announced that it now has over 500 million registered users, an increase of some 100 million in the last five months, and of 400 million in the last two years. Mark Zuckerberg has already told us that it is "almost guaranteed" that the site will eventually reach a billion users, but with no indication of when he thinks that might happen.