Shared, or semi-dedicated proxies are named quite accurately. Service providers that offer shared proxies lend a single IP to several customers. Generally speaking, the number of concurrent users is small, but there’s no official rule on the maximum allowed number. So, while your actual address is hidden, you don’t have complete control over how the proxy is used.
While this might sound a tad dodgy to you, it is nothing to be concerned about. People choose shared proxies because they come at a lower price point than dedicated proxies. They are also cheaper for proxy providers to maintain and offer you a better bang for your buck by distributing the cost over the multiple users sharing the same IP addresses.
Another benefit is a larger pool of IP addresses. Let’s say the provider has 100,000 proxies and 10,000 customers. They could only offer ten dedicated proxies to each client, but each would receive exponentially more IPs if the proxies were shared among users.
What puts shared proxies on our radar is the anonymous benefit of a large proxy pool and the lowered costs. The main drawback is that other clients may get the IP banned on websites you also wanted to access. If you’re a beginner, you might as well consider them to test out your scraping skills.
While not spotlessly efficient, shared proxies do their job in fooling websites into thinking you’re from a different country. They may think you’re browsing from the US while you’re currently on your exotic getaway in Thailand. This way, you can increase your anonymity on the web and bypass geo-restrictions.