[Praxeologue]

Their there, now. don't be such a grammar Nazi.

When a website misses obvious grammatical errors, their overall credibility falls into question.

[FredZarguna]

Those of us with grammatical Eros can’t tolerate grammatical errors.

[Bigg Red]

When a website misses obvious grammatical errors, their overall credibility falls into question.

***
Exactly. Usually causes me to stop reading the article. If the writer can’t be bothered checking his English, how careful is he at checking his facts?

[LachlanMinnesota]

I don’t like mixing tenses, either:

“a website”...”their”

maybe “its” would be better