widgix - tools for web marketing and research

If you want to quickly take the pulse of your site, brand, or product against your competitors (or against anything else) you might a look at these two mashups of web services.

Alexaholic lets you compare the Alexa traffic rankings of up to five websites side-by-side.

For a slightly silly, but still useful Google snapshot you might compare any two terms (like your product name and competing one) on GoogleFight. This compares the number of found results for a topic, in other words the number of sources that mention your term(s).