So as part of their effort to make the web a safer place, Mozilla moved to block them late Friday night.

"Because of the difficulties some users have had entirely removing the add-on, and because of the severity of the risk it represents if not disabled, we contacted Microsoft today to indicate that we were looking to disable the extension and plugin for all users via our blocklisting mechanism," Shaver blogged. "Microsoft agreed with the plan, and we put the blocklist entry live immediately."

At a top level, Mozilla's move is in keeping with their recent push to secure add-ons and plugins for its users. It makes sense that Mozilla, rather than waiting for third parties, takes the initiative and protect its users.

Now the issue with the blocking and then unblocking of the .net add-on is a bit messy. Is it, or isn't it secure? What happened between Friday night and Sunday that make Mozilla change their mind? Based on Shaver's comments it looks like there was communication between Microsoft and Mozilla. My take is that there was a reconsideration on Microsoft's part (or a miscommunication) on the severity of the .NET issue.

Perhaps more annoying in this whole situation is the simple fact the no users (to the best of my knowledge) ever actually chose to install the two Microsoft add-on in the first place. Those add-ons were part of a Microsoft Update that got bundled to users earlier this year. That shouldn't have happened in the first place.

Overall though, Firefox users in my opinion should rest assured that Mozilla's management is being aggressively pro-active at ensuring browser security -- and that's a great thing.