First, I really like how you describe so well the flow of social media use: You use one thing a lot, then your interest wanes, and then you use something else.

I agree that synching of social media is vital. I use Selective Tweets to send only certain tweets (tagged with #fb) to Facebook. I did that because I too in those early days of updating my Facebook status from Twitter was annoying my Facebook friends. Or at least I was annoying my husband who was honest enough to tell me.

As for FourSquare, right now I have my setting update only mayorships on Twitter. My thinking was that at least for me getting a mayorship is a rare enough even that it might be of interest to some of my Twitter followers. (At least the ones who live near me.) A fellow student and I went back and forth for a week or so alternating as mayor of the Maxwell School at Syracuse. Folks on Twitter who know us both chimed in on Twitter about the back and forth.

However, I’m open to the idea that even announcing my mayorships might be annoying.

Perhaps there will be a way on Twitter evenutally, where you could select which people get the FourSquare updates. I doubt folks who follow me from other communities care that I just became mayor of the local bagel shop, but my local yokel tweets might. At least a wee bit.

Because my personal and professional lives have blended (perhaps for the worse – hard to say at this juncture), I have a lot of FB people who are more fans of my work than actual friends. For that reason, when I’m working on a story, I tend to update my FB page with Foursquare statuses as a mark of transparency, letting readers know where I am, what I’m covering, and what I’m seeing. I suspect it’s annoying though unless someone cares about the story I’m writing.

Tough call with all social media. Sometimes the most mundane thing results in a wonderfully deep discussion with a near-stranger. Other times, you pour your heart into something and no one cares.

One thing is for sure: Foursquare makes me want to go more interesting places. A quick run-through of my mayorships tells me I eat way too much fast food and spend an awful lot of time at gas stations and Walmarts.

In the earlier days of Twitter, I followed people who used Twitterfeed, that is synced a RSS feed to Twitter, to post every blog post and in some cases comment to Twitter. Few people (that I follow, anyway) have continued to do that as Twitter has grown to be a more valuable network.

Compare that to FriendFeed, which made syncing dozens of services ridiculously easy. It never really caught on and was bought by Facebook, primarily for talent on staff.

I’m not sure if over-syncing leads to a less-valuable network, or if people are more likely to automate services that they don’t value.

And an aside: I found the tweets complaining about Foursquare tweets to be just as annoying as the Foursquare tweets they were complaining about.

Some services you can sync up automatically, others, as you mention, you have to be careful with.