Like vs Such as

From http://gmat-grammar.blogspot.com/2006/06/like-vs-such-as.html

What's the difference between like and such as?

Common mistake we make in there use -

Can you buy me some fruit like apples or pomegranate?

Why the above sentence is wrong?

Use of like in the above sentence mistakenly suggests that the speaker does not wants apples or pomegranate, but rather some other fruit that is similar to apples or watermelon.

In GMAT, like means similar to, and such as means for example.

e.g

Can you buy me some fruit like apples or watermelon?

In GMAT, this sentence implies that the speaker does NOT want apples or watermelon; instead, he prefers some fruit similar to apples and watermelon.

Correct - Can you buy me some fruit such as apples or watermelon?
Apples and watermelon are examples of the type of fruit we want.

I would like you to buy such fruit as apples and watermelon for me.
This is simply a variation -- notice how such and as are separated.

Why should I use sans-serif font for on-screen text?

From http://en.wikipedia.org/wiki/Sans-serif

In print, sans-serif fonts are more typically used for headlines than for body text.[1] The conventional wisdom holds that serifs help guide the eye along the lines in large blocks of text. Sans-serifs, however, have acquired considerable acceptance for body text in Europe.
Sans-serif fonts have become the de facto standard for body text on-screen, especially online. This is partly because interlaced displays may show twittering on the fine details of the horizontal serifs. Additionally, the low resolution of digital displays in general can make fine details like serifs disappear or appear too large.