I don't consider it a trick but there can be a glitch. There is some good advice/tips here.

There is a lot of good answers here Wendy Lawrence .  I always thought that you could tag them IF you were following them or if you were commenting on their post or question even if you were not following them.

If you're connected with them and it's not working, sometimes you have to type their last name first (after the @). It's frustrating sometimes, for sure!

Some with initials are difficult - if you know their first name, type that in, those names with initials often don't pop up. You have to type in first name and initial. 

It is very temperamental for sure but you’ve received some good suggestions 

I'm glad to read that it is temperamental. I thought it was just me having issues as well!

My tagging capability on mobile only works like 5% of the time. That might be part of the issue? -Kasey

that's how it works....there are some that don't work.... or sometimes you need to do it 3 or 4 times before it works....

Wendy,

1.  You can tag someone that commented on your post, even if you don't follow them.

2.  If you are doing that elsewhere, you have to follow them to tag them.

Hope this helps. A

I believe you have to follow a person to tag them unless you are responding to their comment on one of your posts.

Yes, it is tricky.

Some names are like possessed, I figure it's the spirit's way of saying they don't want to be bothered. Kanye West

With very common names you type the @sign and the first name and then a space for the last name until you see it show up. Also- I noticed the Tag feature won't show up in the mentioned person's feed if done via the sub comment feature.

Also, you might need to follow the person in order to tag them. I've suspected this but am not certain because it seems I have succeeded in tagging someone I wasn't yet following.

good question!!  LOL

It is my understanding that we need to be following the person we want to tag. 

There doesn't seem to be any rhyme or reason to it.  Sometimes it works seamlessly, and sometimes it doesn't care what seam you pull at it just won't work.

I haven't been able to discern any logical reason.

It takes patience, sometimes you have to tag the last name.

Wendy Lawrence , See Ron and Alexandra's answer.

It's a little jumpy and takes a bit of patience.

You need to use the correct name. Some use middle initials, etc.

  Sometimes you have to fight with it:

    @wen  @wendy l  @wendy Law  @Wen Wendy Lawrence 

See also the answer from Ron and Alexandra Seigel 

You need to be following the person for the tag to work.

I just put a @symbol Wendy Lawrence & type their name next to it. If it glitches delete the whole thing & do it over. You do have to be following the person to tag them. 

@I wish we knew

It doesn't work with my tablet.

I find that some tags work sometimes but not all the time. Weird.

I believe one of you should follow each other( probably you have to follow a a member you want to tag) or being part of that discussion( for example, to say thanks for a comment).

It can be a little glitchy. If the first name does not work try the last name instead

Similar question... I'm not sure why it works for some and does not for others... must be some kind a of a process rule somewhere in the the back end programming.

Intersting question and great answers. 

It does seem a tad over sensitive.

I find it works now and then only, not all the time.

Try typing last name first.

Yes.

I don'tknow but I wonder if it depends on point total or if they are a paid member or not

Typically they need to already have responded in the question or you need to follow them.

is it someone you follow?  that follows you?

I have had to put a return in, then space back up to make it work.

Beyond my paygrade but sounds like others have helpful answers!

No trick however once in a while...someones does not work as it should