You should look for official sources for exchanges and brokers. Never trust ads or search results! To be sure, access Poloniex's official website and click through to links from there.
Note: Don't even trust the links on this site! Don't trust, verify. Check all links against official sources before entering any credentials.
For instance, Poloniex has these official social media channels.
Prefer them over other sources:
You will find many additional Poloniex news outlets by simple web search.
Although there are thousands of sources, if you intend on trading, you should always rely on your own research.
In crypto, you must be extra careful because transactions are irreversible. Even ads in reputable search engines have been known to point to rogue URLs.
For your security, never access a Poloniex account from a URL you don't recognize or which has been emailed or instant messaged to you.
Normal looking URLs may often direct to an unexpected page which can steal your password.
Don't trust, verify!
In 2017, Poloniex users fell victim to a fake application published on Google Store. This is one example where even a reliable source such as Google can be compromised.
Irreversible transactions make cryptocurrencies especially susceptible to this kind of scam. Users send cryptocurrency to a malicious address and are unable to recover it after they notice the mistake. Malicious mobile apps perform this in the background, without the user noticing anything until they check their balance on a block explorer.
In a few moments time, over 10 thousand users downloaded a malicious application which stole funds from Poloniex account holders.