Actually, Power.com worked a little too well for Facebook's comfort. In late 2008 Facebook started complaining about Power's ability to store Facebook users' passwords and access Facebook users' content. After all, Facebook has its own scheme for connecting to multiple networks at once, called Facebook Connect. Facebook eventually filed suit when talks with Power.com failed to yield an agreement. Power.com says the two companies are now working out their differences. It's likely that Power will still support Facebook, but will have to use Facebook Connect to connect. Without a workable agreement with Facebook, Power.com's utility would be seriously limited. (http://www.power.com/)

Tweetag

Twitter proved itself during 2008 and will keep growing in 2009. Millions of people around the world are adding content (in short dispatches called "tweets") to the Twitter stream every day. Some of this content is worth reading--serious discussions, not just idle chatter.

Tweetag is a sort of search engine for "tweets." It allows you to look for trends in what is being publicly discussed on Twitter, and, more importantly, find discussions of things that matter to you.

On Tweetag's front page you can see a tag cloud showing the most discussed topics on Twitter right now (as I write this, the biggest tag is "Inauguration"). You can search for Twitter messages containing a particular keyword. Once you've done that, Tweetag suggests other keywords to help you narrow down your results. Using tabs, Tweetag organizes the tweets in your search results based on whether they are "re-tweets" (another Twitterer seconding an idea), or replies to tweets, or if they contain questions or links. (http://www.tweetag.com/)

Hi5

Believe it or not, Hi5 is the third largest social network in the world. Yet it's virtually unheard of in the United States. That could change. Hi5 typically has 60 million unique visitors every month, most of them from abroad (40 percent comes from Spanish-speaking countries). Word has it that more and more people in the U.S. are discovering the site, a trend line that will likely keep bending upward in the next 12 months.

The site's music and video applications rival those of other, more popular social networks, and Hi5's mobile app (pictured) is first rate. Hi5 won't be bigger than Facebook in the U.S. by the end of the year, but it will have grown significantly, and it will have given many of us an attractive alternative to try out. (http://www.hi5.com/)

Tripit

Tripit's goal in life is to be your personal, full-service travel assistant. For me, a typical trip (business or pleasure) involves a number of modes of travel--planes, trains, taxis, and so on--and things like restaurants and hotels. It adds up to a lot of details to keep track of. My usual method is to make a hard copy of all my reservations, staple them together, and carry the whole bundle with me.