Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Trulia (NYSE: TRLA), which provides web and mobile-based housing information to prospective homebuyers and allows real estate agents to list their homes, popped as much as 10% following positive news from the Mortgage Brokers Association regarding mortgage applications and after announcing a partnership.

So what: First off was the MBA mortgage application index, which demonstrated a ridiculous 14.8% growth in the first week of March as mortgage rates again fell. Loan requests for home purchases also rose 15%. With more people actively looking for homes, this bodes well for Trulia's business. Trulia also announced a partnership with multiple listing service Midwest Real Estate Data through its Shared Success program. Deals like these are what could give Trulia an edge, especially in mobile applications, and separate it from the competition.

Now what: Today's news from the MBA that applications spiked as rates fell really shouldn't come as a shock. Homebuyers are getting far too comfortable with lending rates remaining at record-low levels, and any move higher in rates lends to a sharp decline in applications. My concern for Trulia lies two to three years down the road, when lending rates begin to rise. Will online and mobile services like Trulia have the capital and cost-cutting ability to survive? I'm still not certain.

Craving more input? Start by adding Trulia to your free and personalized Watchlist so you can keep up on the latest news with the company.