Most common TT spelling mistakes

Maybe boarded to death but at least s/he is lying on the beach and not laying on it.

I should have checked. The "boarded" person is not a native English speaker.

A native speaker just posted a request for "advise" about "itenarys."

In India, I've never heard Eurail, only Eurorail. Before taking a Eurail pass, I thought Eurorail was correct!

Eurail becomes Eurorail on 50% of posts...correcting is hopeless!

Lots of English words have changed their spellings over the years, especially when the 'accepted' spelling was unnecessarily complicated/ irregular. This process will carry on no matter what anyone thinks. This year's 'mistake' will be next year's 'correct' version. What you think is 'correct' might have been wrong a few years ago.
There's always been an element of 'fashion' to English spelling.
Get used to it.
Chill out.

As long as the meaning isn't affected, who really cares?
(Especially on a forum such as this which is used by lots of non-native speakers).

"I" "really" "care."

What about posts with plurals after an apostrophe such as "I want to take photo's" etc?

#25 The non-native speakers are not the ones making most of these mistakes.

In tourist brochures, 'sights' instead of 'sites'.

Yes, how dare they refer to things to be seen as 'sights'! the nerve!

I sometimes have to stop & think if I mean a site (location) or a sight (something to see).

Many sites are also sights but the majority of sights are not sites, if you follow me.

I always like it when people recommend a certain place and then misspell it- shows how well they know the place... Siena is probably spelled with double 'n' half the time, but Harlem, Bruge, The Hage, etc are also common.

The other one that shows up at least once a day is 'definately'.

Many sites are also sights but the majority of sights are not sites
Aww...but most sights are built on construction sites, aren't they? Doesn't that, in a way, make them sites as well (although not in a tourist's point of view)? For my part, I definately think so.