Tweet Grid is a no-login way to monitor multiple Twitter searches in realtime
When you land on their site, you'll first select a grid layout. You can choose anything from 1x1 to 3x3 on the main page, though once you're inside you can switch to experimental layouts like 2x5 and 1x10 to keep tabs. Pro tip: 1x10 doesn't work so well on a smaller display. Four columns is about as much as I could squeeze out of my laptop's 1280 horizontal pixels.
To limit the textual overload, you can choose to display only updates in a certain language and number of updates to store in each box (last 5, 10, 20, etc.).
By default, all searches update in realtime - though you can adjust the refresh rate to a specific number of seconds if you wish. Hovering over a tweet and action icons appear, allowing you to reply, retweet, DM, favorite, view on web, and even email the tweet.
The interface also includes an area to compose updates from scratch, but you'll need to supply your credentials each time to do so. Just using Tweet Grid for watching searches? Click the hide link and the update fields disappear.
At the very top of the page, Tweet Grid provides three easy eays for you to share your grid (layout, terms, and all). You can tweet it, copy the full link address, or generate a truncated is.gd link in a single click. Tweeting automatically includes the is.gd short URL to save space.
All in all, Tweet Grid is an excellent way to keep tabs on numerous Twitter searches without handicapping your API usage.
Correction: as pointed out by Richard in the comments, Twitter search use doesn't actually ding your API count anyway. Regardless, Tweet Grid is still awesome!