IMHO, yes. See, there are 2 tendencies here: the visitor feelings about getting these dialogs "in their face" and the site owner's needs.
In the first case, visitors might be annoyed, so the task of the experience designer is NOT to prevent these dialogs, but to find the proper way to compensate this perceived annoyance with a greater benefit.
As a site owner... well, this mechanism, if well used, is an incredible way to increase CTR and ROI. But dialogs alone are not the only aspect to consider, because IF BAD USED, you're only providing an experience the visitor won't probably want to go through again. Basically, avoid your site as much as possible.
I won't go deep into the marketing mechanisms and techniques and the psychological aspects of these dialogs, but as an example, something I have tested myself in many sites and there are many studies on 3rd parties as well:
- Bad Message: Thank you for visiting my site, like us on Facebook!
Why? I don't even know you and I don't get any benefit from this!
- Bad Interaction 1: Dialog shows "on load"
User can't see why should they pay attention to the dialog (although some studies shows that, when coming from search engines, this increases CTR at the cost or a reluctant visitor)
- Bad Interaction 2: Dialog shows on every page, or every time the user refreshes/reloads
This is a direct way to scream your user "I don't want you around anymore!"
Please note that these are not the only bad aspects, just 3 of the most known
Now, here comes the big question: who is the most important user? Visitor A who visits the site to get some content, Visitor B who entered the site doing an unrelated search, Visitor [n] who [some persona characteristic] or Site Owner who maintains the site to serve the content to **Visitors A, B, [n] hopefully making a profit?**
Well, the fast, "politically correct" answer is ALL OF THEM, but in reality, if you take one element out, it all goes "kaboom!": for example, take the profit out of the equation, there's no more site, hence no site owner, hence no content, hence no visitors. And this is something many people forgets in their purchase of correctness.
Then, you have the UX torturers: they will do every nasty trick to skim money off the user pockets, even if it means losing the user for good afterwards (they just repeat and rinse). They usually work on mechanism affecting content, and therefore users get frustrated. So the equation gets null values as well (however, this is a metaphor, I won't argue that some UX torturers have a valid strategy for their goal, and it can be easily measured by income, just talking in terms of usability. Game UX Torture is a solid sample on how to torture users to make money)
So, what you need to do is to create something that supports the site while providing the best possible experience to the user so he/she comes back again, refers your site, shares it, purchase and whatever positive outcome you may want for your site. For this, it's a good idea to keep the UX principles in mind
So, when to use?
Here you have a list of situations (included yours) of when to actually use this solution
You want to interrupt current process and catch the user’s full
attention to something really important.
For example to notify the user about some major changes to you service since the last login, tell the user that his login has expired
and provide a login form to let him login again, warn the user about
doing something that is not reversible etc.
You need to display application preferences or other options that are
“independent” from other pages.
Placing them in an overlay saves the user a return trip to another page and makes it easy to get back to the original page where he came
It is important to show additional or related content/options in
E.g. user wants to view suggested products related to the one he is viewing without losing the current page (see example).
Another example is using modal overlays for showing larger versions of images and videos.
You need to get input from the user.
Overlays work well for showing forms for feedback, sign-up, contact, etc.
Bibliography and Resources
As you may imagine, this has been studied a lot, but here you have some material to go deep into the subject