Update (1:01 p.m. EDT): Linkedin's blog is back up, but there's no archive or anything to indicate a Syrian connection. Just an announcement of the company's new iPad app.
The striking thing about the "Syrian Electronic Army" attack on LinkedIn's blog is that, well, they attacked LinkedIn, which really seems to have very little to do with the conflict in Syria. On Thursday, the Linkedin blog is down, but before it went dark, Silicon Republic's John Kennedy reports, it bore an image of a Syrian flag, with President Bashar al-Assad standing in front of it, and this text : "We are a group of Syrian youth who wanted to show the truth and therefore we used this website which was used to spread lies about Syria." As violence escalates in the war-torn country, this seems like an oddly tangential target for cyber-attack.
The SEA usually attacks targets that make obvious sense to its pro-regime propaganda campaign. This week it hacked into the Saudi Arabian channel Al Arabiya and planted false news reports about an apparent coup in Qatar, which joined Saudi Arabia in calling for Assad to step down. It's has been known to go after questionable targets, but they usually have some identifiable reason. For example, last August they deluged an unofficial Columbia University Facebook page they thought was the real thing, apparently in response to a Columbia professor's comments to The Wall Street Journal saying the Syrian government was "in trouble because of the Arab Spring."
Linkedin has an even more tenuous connection to the Syrian opposition, as far as we can tell. Aside from a brief incident in 2009 where the service blocked people with Syrian IP addresses, there's no connection between LinkedIn and really anything in Syria, except for the fact that people sometimes use the social networking service to share news. Unfortunately, with the blog down, we can't exactly read back through the archives to see what annoyed the SEA so much. So for now, their plan is working.