Ghonim, Google's head of marketing in the Middle East and North Africa, wasn't politically inclined, according to news reports, but was interested in tweeting on the protests, which exploded in Egypt on Jan. 25. Following similar events in Tunisia, protesters called for the ouster of Egyptian president Hosni Mubarak.
One of the last posts on Ghonim's twitter account was "Pray for #Egypt. Very worried as it seems that government is planning a war crime tomorrow against people. We are all ready to die #Jan25."
Ghonim's wife and brother last heard from him on Friday. His wife told Al Jazeera English on Tuesday that she is very concerned about him and is seeking information about his whereabouts.
A Google spokesperson in an e-mail on Wednesday said, "I can confirm that a Googler, Wael Ghonim, is missing in Egypt. He has not been seen since late Thursday evening in central Cairo. The safety of our employees is very important to Google, so if anyone has any information we're asking that they please call the following U.K. number: +44 20 7031 3008."
In related news, Google, Twitter and recent Google purchase SayNow have joined up to allow Egyptians, who have had Internet access blocked by the government, to tweet about what's happening on the ground with a new service.
It allows users to leave a voice mail at one of three international phone numbers (+16504194196 or +390662207294 or +97316199855), and the messages are instantly dictated and posted in English at twitter.com/speak2tweet.
"We hope that this will go some way to helping people in Egypt stay connected at this very difficult time" said a post on Google's official blog.
"Our thoughts are with everyone there," wrote Ujjwal Singh, co-founder of SayNow, and AbdelKarim Mardini, Google product manager for the Middle East and North Africa.