But there's also a difference (or: But there's a difference, too,) in where they can appear in a sentence. In the other thread, Panjandrum's examples show that 'also' doesn't like to come at the end of the sentence, which is probably the preferred position of 'too'.
- I'm going to the party; I'm going to the restaurant
too.
- I'm going to the party; I'm
also going to the restaurant.
They can both come in the middle of the sentence, but they don't necessarily mean the same thing:
- I,
too, like beer (= 'other people like beer, and so do I')
- I
also like beer. (= ambiguous: either 'I like beer as well as wine', or 'other people like beer, and so do I', possibly depending on intonation)
'Too' doesn't like to come at the beginning of the sentence (unless it means 'excessively')
Also, I think we should change the title.
I think,
too, that we should change the title.
Too, I think we should change the title.
I can't quite work out the rules, but this gives you an idea. 'Too' seems to have a gravitational pull towards the end of the sentence. It seems to qualify what precedes it. 'Also' has a gravitational pull
away from the end of the sentence (not necessarily to the very beginning, but towards the beginning).
(I'm still perplexed, though: why can we say 'I also like beer' but not 'I like also beer', when we would say 'There's also a difference' but not 'There also is a difference' (at least in British English).
)