You can setup Google analytic to get the details about the actual traffic on the website. It will give you detailed information about the website traffic.
I would like to give the best advise here. Find the blogs which have a blog post of classified listing website. Contact all the blog owners and ask them to add your website to their classified listing post. You can also comment and add your website to this type of posts. The traffic of your...
Profile linking means when you create a user profile on any website which offer a user profile. Once you create the account and fill all the details like name, dob, about, website url etc.
You can call it Google Updates. Google publishes algorithm updates regularly means they do changes in their search algorithm to fight with spam and provide better search results to their users.
If you want to increase Google plus page traffic then you have to post regularly, follow relevant groups, follow relevant people, Plus 1 and comment on other people's posts. It will surely help you in increasing Google Plus page visits.
Search traffic in webmaster has many options. First one is search analytic, It shows you total clicks your website got from SERP. You can get a list of keywords also. Second one is "Links to your site". It shows a list of websites from where your website is getting backlinks.
Impression means how many times your ad displayed in search results or anywhere(if display ad) and click means click or visit your ad get in search results or anywhere (if display ad). If you have high number of impression and less clicks then you should optimize your add to get more clicks.