Google is very keen about their webmaster guidelines. There are many points you can found in their guidelines. Every point is very crucial and every webmaster must follow that rules.
Recently Google stat that they will take strict action on those sites who running widget with keyword rich anchor texts. Those sites which does not provide any value to their users & use widget in suspicious manner.
Few snapshots given by them below:
Even in Google official webmaster guidelines they mention about Widget links.
Google stat below line in their guidelines.
Keyword-rich, hidden or low-quality links embedded in widgets that are distributed across various sites,
for example: Visitors to this page: 1,472
Is this sign to take closer to Google Penguin?
Google Penalty Recovery Expert Marie Haynes stat on Twitter:
New Google announcement re links in widgets. When Google announces something, pay attention. Penalties may follow. https://t.co/PNhnWheKC5
— Marie Haynes (@Marie_Haynes) September 8, 2016
It is sign by Google that they are very aggressive to take action on such sites that violates their guidelines and this might be a closer to penguin update too. Recently on Google hangout, John Muller says that “they are close to announce the Penguin update” so we hopefully consider this is sign that they are running on prior level to launch the update soon.