In short, yes. Tagboard has legal authority to publicly display social media content and here's how.
Every social network has users accept a 'Terms of Service/Use' or 'Statement of Rights and Responsibilities' that gives the social network and its PARTNERS a license to share and display public photos. These partners include social media search and display platforms like Tagboard, who legally pull the content through the networks’ APIs, and comply with their requirements for partnership – such as, including network logos and author avatars on all posts. In addition to this explicit right, the Tagboard platform only ingests social posts which have been marked as Public and remain on the source network.
Don't take our word for it though. Here are excerpts from, and links to, the big three network's complete terms of service (TOS):
"When you share, post, or upload content that is covered by intellectual property rights (like photos or videos) on or in connection with our Products, you grant us a non-exclusive, transferable, sub-licensable, royalty-free, and worldwide license to host, use, distribute, modify, run, copy, publicly perform or display, translate, and create derivative works of your content (consistent with your privacy and application settings). This means, for example, that if you share a photo on Facebook, you give us permission to store, copy, and share it with others (again, consistent with your settings) such as service providers that support our service or other Facebook Products you use."
"You give us permission to show your username, profile picture, and information about your actions (such as likes) or relationships (such as follows) next to or in connection with accounts, ads, offers, and other sponsored content that you follow or engage with that are displayed on Facebook Products, without any compensation to you."
"By submitting, posting or displaying Content on or through the Services, you grant us a worldwide, non-exclusive, royalty-free license (with the right to sublicense) to use, copy, reproduce, process, adapt, modify, publish, transmit, display and distribute such Content in any and all media or distribution methods (now known or later developed). This license authorizes us to make your Content available to the rest of the world and to let others do the same."
In most standard redisplay use cases, displaying social media content on a website or at an event does not remove the content from the protection of the network’s TOS above, provided you do so through a partner of the network--Such as Tagboard and use the content for adjacent marketing. Adjacent marketing means the content exist near direct advertising or marketing, but the content itself is not a part of an advertisement. For UGC in a direct marketing campaign please see this document: https://support.tagboard.com/docs/redisplaying-user-generated-content