Is ‘Everybody’s cup of tea’ a well-used English idiom?

Solution 1:

It is a well-known idiom in US English. (I'd be surprised to find that it wasn't equally well-known in Britain, but I have no personal experience.) Your definition is quite accurate. However, it is almost always used in the negative: not someone's cup of tea.

Solution 2:

You have the definition down pretty well. The FreeOnlineDictionary writes:

cup of tea

1. Something that one excels in or enjoys: Opera is not my cup of tea.

A different definition refers to something being markedly different from another, as z7sg pointed out. It refers to two subjects being separate, although this usage is more suited for the phrase "a different kettle of fish".

I've personally heard it referred to in both American and British English, though I can speak only for American English. I think it can definitely be applied to anything -- there is no limit. For example, you might say

Social networking is not my cup of tea.

if you weren't particularly interested in joining Facebook, Twitter, etc. The sentence you quoted is saying that "Facebook friends are not to everyone's liking", and supports this by saying that the author is "old-fashioned" and doesn't want such a "superficial relationship". He is saying that "Facebook friends aren't for me, and here is why".

Edit to address follow up question: You can't replace tea with another edible such as coffee or cake. The accepted idiom is "cup of tea". There is, however, the related phrase "another kettle of fish".

Solution 3:

Yes, you are correct it is a well-used British idiom meaning "not to someone's liking". There aren't really any restrictions on its use, you can say "that's not my cup of tea" to anything. It can also be used in a positive sense "that is my cup of tea" but this is less common.

The origin of the phrase is simply the very high regard for tea that is held by the British.

Solution 4:

Your deduction, that "not everybody's cup of tea" means "not to everyone's liking", is absolutely correct. The expression commonly used in both the affirmative and negative sense; for example: "I would say it's definitely his cup of tea", or "that isn't exactly my cup of tea".

However, while commonly used and readily understood (at least in Australia), I would hazard to say that it is more of an older person's expression of choice in describing something they do, or don't have a penchant for.

I also agree with Simchona in that use of the expression "another cup of tea altogether", to mean "another/a different kettle of fish", is fairly uncommon... (I can't say I've ever heard anyone state "another cup of tea" in that sense.)