Usability of Popup sharing / search toolbars on websites

Question

I've been noticing an increase in sites that are using a dropdown / popup sharing and search panel

(The main site of note being http://www.uxmatters.com/)

Is there any research into whether this aids or hinders usability? Is this actually a useful feature of websites? My personal opinion is that it distracts me from the content of the site - it appears just as I start scrolling to read the content and thus pulls my eyeline off the content and onto the new popup. However, I don't just want my subjective opinion, has there been and studies on features like this?

All I can find is from the website of the main company responsible for this feature - http://www.apture.com/ who state:

Apture Search Is a Proven Win

The data doesn't lie - Apture increases visitor engagement by leaps and bounds. We help you track your visitor data and how effective our tool is for you. There's no downside.

Naturally, I'm loathed to believe their own sales pitch, however with the growing ubiquity of it, and it's inclusion on UX MATTERS I'm curious as to it's benefits.

Answer 1

I don't have any hard data, but here is my thought as to why.

The bar popping down may be bad UX but it adds functionality to the site. The bar on uxmatters (which personally has very bad UX, but we can discuss that in chat) offers:

1. Sharing

2. Search

3. Logo/home link (quick navigation back to the home page even when scrolled)

In a study on what people value the most in a site, functionality was first and user experience was second. So the fact that the bar offers new functionally for these sites, search being a huge one that users love and appreciate, and sharing will help keep them engaged, is what is causing these numbers.

I would wager that if that new functionality was integrated into the site, rather than on a distracting bar, the increase in engament would increase or at least stay the same.

(P.S. I will try and dig up that study on site worth)