Modi has featured at the top of the list for at least a couple of years now and is followed this year by Congress president Rahul Gandhi.
M J Akbar, who resigned as Minister of State for External Affairs after allegations of sexual harassment, also featured on the list at number 6, behind alleged economic fraudsters Vijay Mallya and Nirav Modi.
The excitement surrounding Bollywood's biggest wedding ensured actors Deepika Padukone and Ranveer Singh were 'couple' newsmakers.
At under two years, Taimur Ali Khan was the youngest entrant to this list -- the son of Kareena Kapoor and Saif Ali Khan boasts a formidable following online.
Also joining the list was actress Priya Prakash Varrier, whose wink in the Malayalam film Oru Adaar Love "almost broke the Internet", the statement by Yahoo said.
"There was plenty of fake news swirling online in 2018. Did Modi really touch Owaisi's feet? (photoshopped!), Modi hires personal make-up artist for Rs 15 lakh a month (an old photo from when Madame Tussaud's took PM Modi's measurements) and Rahul Gandhi holds woman's hand on stage (taken before a large group lifted hands in solidarity at a Jan andolan rally)," the statement said listing out the top three fake news doing the rounds online during the year.
Year in Review (YIR) chronicles the top choices of Internet users in India, spotlighting the newsmakers, stories and topics that went viral and were trending online during the year, the Yahoo statement said.
It is based on users' search habits and a selection of what they read, recommended and shared most on Yahoo.
"Over the last decade, YIR has documented the growing empowerment of the country's online audience, seen in the expression and sharing of new ideas online. This year, the collective power of India's Internet users fuelled the watershed #MeTooIndia movement. India's #MeToo Survivors, who started a conversation with wide-reaching impact, are YIR's 2018 Personality of the year," it said.
The year saw several women taking to social media to share accounts of sexual harassment by men in positions of power. The movement crossed over to the mainstream, garnering huge support and mobilizing every section of the media, it said.
The Karnataka election -- one of the most important events on this year's political calendar -- was the Most Searched for Term in 2018. A HuffPost India investigation into the hacking of the Aadhaar software came in at No. 2 on this list, sparking a nation-wide debate and trending online, it noted.
Scam-riddled Vijay Mallya and Nirav Modi also bagged spots on the list of Most Searched for Terms in 2018.
RBI Governor Urjit Patel came in at the top of 2018's Finance Newsmakers, holding his own against the government. India's richest man and Reliance Industries Chairman Mukesh Ambani -- whose wealth reportedly increased by Rs 300 crore per day in 2018 -- came in second on this list. Brother Anil Ambani, Reliance Group Chairman, also features on the list for the Rafale deal controversy, Yahoo said.
"Users bid farewell to Bollywood actress Sridevi with an outpouring of grief and love online, making her one of the Most Searched for Female Celebrities in 2018. They also rooted for Sonali Bendre, who shared her fight against cancer online with #switchonthesunshine, putting her on the list," it said.
Sunny Leone was the Most Searched Female Celebrity yet again, with Priya Prakash Varrier coming in close to the top.
"Salman Khan proved he was the 'biggest boss,' as the Most Searched Male Celebrity of 2018," it said adding that American singer Nick Jonas was a close second as he zoomed up the list with his engagement to actress Priyanka Chopra.
"While staying loyal to Ranveer-Deepika, users also brought in newbies like actor Janhvi Kapoor, and Sara Ali Khan, besides Sprinter Hima Das into India's Top 10 heartthrobs of 2018," Yahoo said.