1) I was invited along to the party.

The way I see it, '1' means a person or some persons were invited to the party. I was invited to go along with them. But I am not sure whether it is clear who invited me. Was it those who were throwing the party or the person or persons whom I was invited to join?

Was it:

a) We are invited to Tom's place. Why don't you come with us?


b) Pete and Harry and James are coming to my place. Why don't you come along with them?




The given sentence 1) would generally have an uncomplimentary sense: you were not invited to the party, but some people you know, who were invited, told you that you could tag along with them to the party. This could create an awkward situation: the people who threw the party might not welcome you there, and it might be a long night for you there.