Metta, incorrect.

Situation #1. If SMTP is disabled.

If SMTP is disabled verification email is sent right away.
User can send himself as many verification emails as he wants to.

Situation #2. If SMTP is enabled.

If SMTP is enabled verification emails are sent by Cron.
If your Cron is set to run every 24 hours, then verification emails will be sent once in 24 hours.
If your Cron is set to run every 15 mins, then verification emails will be sent once in 15 minutes.

If SMTP is enabled, does it Also mean that notifications are also sent after 15 minutes when cron runs (set to 15 minutes), in users profile. or will they appear instantly?

Vishal, yes. Notifications ( we are talking about Activity Notifications plugin) are always connected to Cron, no matter whether SMTP is enabled or not.

I would then say my cron is set to 15minutes but i receive activity notification within fraction they are posted. Then why is that so?? Is there any problem then??

Vishal are you talking about activity notification emails or notifications within the upper right console like in my screenshot?

I'm talking about screenshot one. 

Thanks so much, Alia, for your helpful feedback.  I've included a few follow-up questions below, and I will (again) be looking forward to your feedback and follow-up.

Thanks,
Metta

(1) Email Verification Messages
I checked my site and SMTP is NOT enabled.  However, I was previously having trouble sending multiple email verification messages.  If we have this issue again, I will check in again.

In the meantime, can you think of any reason why it might NOT be possible to send multiple verification emails if SMTP is NOT enabled?

(2) Activity Notifications
Where can I read more about the "Activity Notification" plugin?  I have not used it before, I'm not familiar with how it works and I could not find anything in the Oxwall documentation about how it works.

(3) Recommended Chron Time Frames
Do you have any general guidelines and/or recommendations about how Chron Time Frames should be set?  My host set the chron job for me, I don't know everything that the chron job governs, and I'm not sure what time frame settings would be best for my site.

Metta,

>>In the meantime, can you think of any reason why it might NOT be possible to send multiple verification emails if SMTP is NOT enabled?

Correct me if I am wrong, you are trying to send one user several verification emails, but NONE of them is coming? or only one is comiing?

>>Where can I read more about the "Activity Notification" plugin?  I have not used it before, I'm not familiar with how it works and I could not find anything in the Oxwall documentation about how it works.

We don't have detailed documentation. But you can register and test this feature here: http://demo.oxwall.org/email-notifications

>>Do you have any general guidelines and/or recommendations about how Chron Time Frames should be set?

It all really depends on which plugins you are using, number of users on your site, and your server's capacity.

Of course running cron every minute is the ideal solution. BUT you might not want to load your server so much. Many of Oxwall users set their Cron to run every 15 mins - seems to work fine.

Re: Email Notifications
-- I was testing the login process on a new site and was attempting to send multiple email verificiation messages to my new test member.  Only the first notification was received even after multiple attempts to resend the email verification message.

Also, FYI: I'm testing the "Activity Notification" plugin now -- and I'll check with my web host to see what the chron settings are for my installation.

Thanks,
Metta

P.S.
Is it safe to assume that:
-- I will only receive notifications about other people's activities, and
-- I will NOT receive notifications about my own activity?