Alerts.com lets you create custom online widgets for job searches, daily weather, price watches, sports scores, and many more. You can tell it to send you a wake-up call (it will actually call your phone).
Alerts.com is the easiest of the searches to use if you aren't sure what to search for. Alerts.com just spells out the options for you, and you pick the ones you want.
Google Alerts, Yotify and Alerts.com are the biggest three services designed for all-purpose automated alerts. But you can use other services to search other kinds of information in very powerful ways.
You know Twitter as a microblogging tool. Some people "get" microblogging, but most don't have the time to sit there and watch a constant barrage of inane chatter.
Think of Twitter as a source of fast-breaking news, fed by millions of people. When anything important happens, Twitter messages go out instantly.
I realized this when I happened to be watching Twitter and an earthquake in Silicon Valley hit. People posted Twitter messages about the quake before the earth even stopped quaking. Breaking news is usually posted on Twitter before any other source in the world.
There are many ways to use Twitter for alerts. I use a serviced called TweetBeep, which constantly scans Twitter chatter and e-mails you when your search criteria pops up.
TweetBeep has some surprisingly powerful search options. You can, for example, eliminate Tweets without URLs, or search only messages from a specific user.
WatchThatPage monitors individual Web pages, and sends you an e-mail when they're changed in any way. It's ideal for pages rarely updated because it lets you avoid wasting time checking and re-checking. This is a great way to stay updated on the personal pages of friends, and also the home pages companies you're interested in.
After setting up an account, click on the Pages tab, then paste in the URL of your choice into the "Add page" box, then click Add.
And one parting tip. The biggest barrier to adopting these services is the question, "Er, OK, what do I search?" That answer will come to you later. In the meantime, set up one search on each of these services just to send reminders to you until you think of things to use them for.