Expedia (EXPE) Expedia stock fell more than 4% in Tuesday morning trading after the company’s Internet traffic was seen to drop sharply.

According to Internet traffic metrics, Expedia’s visibility on Google (GOOG) search engine results has fallen 25% over the past day or so. Visits to Expedia’s website are also down sharply. SearchEngineLand says that Expedia’s ranking in search results for generic travel-related search terms has fallen because Google is penalizing the company for trying to boost its search engine results through paid-linking, in which a company or outside search engine optimization firm posts a large number of keyword-heavy links to drive search engine traffic to a specific website.

Google has punished a number of websites for the practice, including Rap Genius, which suffered a sharp traffic drop after receiving a 10-day penalty from Google. Over the past day or so, Expedia’s ranking has declined significantly for search engine queries that use common keywords including airline tickets, cheap hotels, vacation and rental cars.

A partnership with Travelocity boosted Expedia stock in August, helping Expedia stock recover from a steep drop in July.

On news of its SEO problems, Expedia stock fell more than 6% in early Tuesday trading, but Expedia stock recovered somewhat in mid-morning trading. Expedia stock has gained more than 14% since January 2013. Expedia stock surged in October after the company posted better-than-expected quarterly earnings.