In terms of activities:

• Can support peer and group assessment 
• Can replicate authentic tasks, I.e. blogging, producing videos, scenario-based learning, etc 
• Various media formats, broader range of tasks for formative use. 

In terms of feedback:

• Improved clarity and understanding of feedback: more accessible and potentially engaging with various media offered, and more legible in the case of written feedback  
• Speedier feedback, especially if automated. Creating common comments or recording your feedback can be less time-consuming 
• Variety of formats to provide more detailed and richer feedback
  
• Students can potentially access feedback anytime, from anywhere, and so refer to it at a later stage in their learnign journey

Most of the challenges of online formative assessment relate to the technical aspects of using technology, including:

• technical fails (website crashing, loss of connection, etc)
• support available, i.e. is it supported by the University and how?
• compatibility (devices, versions, etc)
• sustainability: "with technology evolving at an increasingly rapid rate, aspects of it are likely to become outdated very quickly" (Deeley, 2017)

From a student and/or teacher perspective, it is also worth noting:

• level of digital literacy needed. Support may be required with using the tool and it may be time-consuming when learning how to use it. It can also lead to extraneous cognitive load for the students if the tool is not intuitive.
• learning needs and disabilities. While technology is often hailed as a way to address these needs and diversify the types of feedback formats available to students , some may not be accessible to everyone (e.g. audiovisual).
• potential resistance to new methods

• Select tools that are user-friendly and recommended and/or supported by the University
• Set aside some time to familiarise yourself with the technology. Check what kind of support you can get (online guidance, training, etc.)
• Look for case studies and examples of use in practice for lessons learnt and tips, and to ensure that you select the most appropriate option in relation to your learning objectives. Talk to your colleagues and the Educational Technology Team about your ideas.
• Make sure that you set clear expectations and instructions for  your students and support them with using new activities and tools.

Black and William's strategies regarding formative assessment (Black and William, 2009) are often cited as a starting point to understand the potential of formative electronic assessment.  Indeed, most of the literature around this area seeks to understand its potential to support the five strategies that they have identified:

1. engineering effective classroom discussion, questions, and learning tasks that elicit evidence of learning;

2. providing feedback that moves learners forward;

3. clarifying and sharing learning intentions and criteria for success;

4. activating students as owners of their own learning; and

5. activating students as instructional resources for one another. (Pachler et al., 2010)
   

Gikandia, Morrowa and Davisa (2011) offer a very thorough literature review of online formative assessment in higher education.

Jisc, a membership organisation offering advice on digital technology for education and research in the post-compulsory sector, has published many resources on e-assessment (Jisc, 2010; Ferrell and Gray, 2013), including a report on integrating formative e-assessment in post-16 education (Pachler et al., 2009) and resources on specific approaches to formative e-assessment such as e-portfolios or peer assessment.

Black, P., & Wiliam, D. (2009). Developing the theory of formative assessment. Educational Assessment.Evaluation & Accountability, 21(1), 5–31

Ferrell, G and Gray, L (2013). Electronic Management of Assessment: Using technology to support the assessment life cycle, from the electronic submission of assignments to marking and feedback. Jisc [Online] [Accessed 15th May 2019]. Available from: https://www.jisc.ac.uk/guides/electronic-assessment-management

Gikandia, J.W., Morrowa, D. and Davis, N.E. (2011). Online formative assessment in higher education: A review of the literature. Computers & Education, 57 (4), 2333-2351.

JISC (2010). Effective Assessment in a Digital Age: A guide to technology-enhanced assessment and feedback. England: HEFCE.

Pachler, N., Mellar, H., Daly, C., Mor, Y. William, D. and Laurillard, D. (2009).Scoping a vision for formative e-assessment: a project report for JISC. London: Institute of Education.

Pachler, N., Daly, C., Mor, Y., & Mellar, H. (2010). Formative e-assessment: Practitioner cases. Computers & Education, 54,715–721