WordStream, a maker of software that suggests keywords and keyword strategies for search advertisers, launches its flagship (and only) product today. The application not only generates a database of relevant keywords, but also tracks their performance to determine which ones work best, in which groups and why — and puts the results to use in live campaigns. It also announced $4 million in first-round funding from Sigma Partners.

The Boston-based company says that it automatically integrates analytics to prioritize certain keywords, allowing advertisers to make informed decisions at all times. The keywords themselves are continuously chosen based on traffic data, and the software also organizes negative keywords — those that they don’t want their brands associated with. Wordstream is offering the product on a monthly subscription basis, charging between $300 and $1,000, dependent on the features, support options and account requirements users choose.

Web-based advertising might be taking a hit, but there is evidence that search marketing will only dip a little as display ads bear the brunt. On top of that, software-as-a-service companies that are able to cut costs for marketers, like WordStream promises to do (by saving labor time and eliminating need for other costly analytics tools), are actually predicted to fare pretty well through the downturn.

WordStream plays in the same space as companies like Clickable and SearchForce, which also suggest keywords based on popularity and cost efficiency, monitor results and let users adjust campaigns accordingly.