NEW YORK ( TheStreet) -- "Tax filing" is a trending search topic Monday as the April 18 deadline for taxpayers to file their tax returns approaches.

The Internal Revenue Service extended the deadline to April 18 this year because Emancipation Day falls on the usual deadline of Friday, April 15.

The IRS has said it expects to receive more than 140 million tax returns this year. About 70% of all taxpayers used the government's e-file service to file taxes in 2010, the IRS said, as filing tax returns electronically becomes more popular.

"E-filing is becoming the traditional way to pay taxes," a spokesman for the IRS told TechNewsDaily. "We have processed 1 billion e-file returns since 1990 when it first started to take off."

"Solar energy" is a hot search topic as many investors and consumers look to solar stocks as a less risky alternative in the wake of the nuclear crisis in Japan and higher oil prices due to the turmoil in the Middle East.

"Despite the earnings and price target downgrades, solar stocks still have significant upside potential and investors can benefit from these stocks," Karvy Global Research said in a recent article on TheStreet.

Shares of FirstSolar ( FSLR - Get Report) are up more than 15% in the past year, while silicon solar cells maker SunPower ( SPWRA) has seen its stock rise 28% over the past year.

The chatter on Main Street (a.k.a. Google, Yahoo! and other search sites) is always of interest to investors on Wall Street. Thus, each day, TheStreet compiles the stories that are trending on the Web, and highlights the news that could make stocks move.

--Written by Theresa McCabe in Boston.

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