The Web of Science and Scopus databases both have features to enable you to identify individuals and institutions which research in your area.
Consider joining a social media network.
There are a number of sites you can join that will make you more visible to other researchers.
Twitter is regarded as one of the best ways to advertise your recent research articles as tweets are counted in your Altmetrics score. Make sure you include the article's DOI in your tweets.
The most popular social media site for professionals is LinkedIn : a general business/employment network that can be helpful on finding a job, looking for employees, and making contacts. It covers all subject areas.
Popular general networks for researchers include: Many of these sites allow you to ask targeted questions that MIGHT be answered by an expert. This can be especially useful for complex research methodology questions and other niche problems that your local colleagues cannot answer. Of course, you will need to check the credibility of answers.
There are also subject oriented networks such as:
Loop (for science)
The quality of an individual researcher is calculated using a metric called the "h-index"-developed by physicist J.E. Hirsch.
Web of Science defines the h-index as "based on a list of publications ranked in descending order by the times cited. The value of h is equal to the number of papers (N) in the list that have N or more citations."
"A scientist has index h if h of his/her Np papers have at least h citations each, and the other (Np−h) papers have no more than h citations each." (Hirsch, 2005)
Scopus, Web of Science and Publish or Perish all calculate an author's h-index automatically. However, the calculation is based on the content held by the source doing the calculation - so an author's h-index will be different in Scopus, Web of Science or Publish or Perish (which uses Google Scholar).
The newer g-index was developed to give more weight to highly cited articles, while the Contemporary h-index gives weight to recently-published articles.